The Postal Regulatory Commission ruled Thursday that the agency can raise the price in keeping with the cost of inflation. Prices could go even higher as the commission is considering a postal service proposal to raise money.

Declining mail volume continues to plague the postal agency. Some 2 billion fewer pieces of mail were sent in 2013 compared to 2012, thanks to another drop in first-class mail, the kind most consumers use to pay bills and send letters to Grandma.